GB2390951A

GB2390951A - Identifying telecine signals by comparing an inter-field motion pattern with a reference pattern

Info

Publication number: GB2390951A
Application number: GB0316076A
Authority: GB
Inventors: Seung-Joon Yang; Young-Ho Lee
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2002-07-13
Filing date: 2003-07-09
Publication date: 2004-01-21
Anticipated expiration: 2023-07-09
Also published as: US20040008275A1; CN1471323A; DE10331048B4; JP2004040815A; DE10331048C5; GB2390951B; DE10331048A1; US7233361B2; KR100854091B1; GB0316076D0; KR20040006680A

Abstract

An apparatus for detecting whether an image signal is in a film mode, includes a first field buffer (120), a second field buffer (140) and a third field buffer (160) that sequentially buffer respective fields of the image signal by order of input, using the respective fields stored in the first, the second and the third field buffers. The apparatus for detecting whether an image signal is in the film mode, includes a motion information calculator (200) for calculating motion information for the respective fields by comparing variations in the motion in the respective fields stored in the first and the third field buffers (120, 160), a motion information buffer (300) for storing the motion information in units of a predetermined number of fields, and a pattern matching unit (400) for determining whether the image signal is in the film mode by comparing the motion information of the respective fields stored in the units of the predetermined number of fields with a reference pattern. The reference pattern may have a predetermined periodicity in accordance with a 3:2 pull-down conversion, and by subsequently determining whether the motion information matches the pattern a telecine signal may be identified. Independent claims are included for dividing the detected motion by a positive integer prior to comparison of the motion patterns and for determination of motion by counting the number of motion blocks in a field.

Description

239095 1

- 1 Identifying Telecine Signals Description

The present invention relates to identifying tclccine signals I Conventional cine films are shot and projected at a rate of 24 frames per second.

Video signals on the other hand have frame rates of 25 (PAL and SECAM) or 30 (NTSC) fratnes per second. Also, television-type video signals use nvo interlaced fields to form each frame. Accordingly, in order to transmit a cine film by

0 television, it is necessary to convert the frame rate from 24 to 25 or 30 frames per second and introduce interlacing using telecine apparatus.

In the case of NTSC television, two 24 fps (frames per second) frames are spread over 2/ 30 fps frames, i.e. five fields. Film frames are alternately used to form

75 three (odd-even-odd) and two fields (even-odd) of the television signal.

Using the above-described 3:2 pulldown scheme, the two cine frames are converted into the five interlaced television fields. Accordingly, when a cine film is 3:2

pulldown converted and transmitted, the receiver receives all of the original cine 20 frames, i.e. cine frame information is duplicated in the television signal rather than being lost. In other words, the receiver can obtain the original images with high quality using an Interlace-tProgressive Conversion (TIC) process and the 3:2 pulldown converted interlaced fields.

25 Accordingly, the receiver needs to be able to detecting whether the received signal is a telecine signal or a native Video signal so that it can process the received signal optimally. Such film mode detection and image signal processing are also required for the image signals other than NTSC TV signals.

30 Figure 1 is a block diagram showing a conventional apparatus for detecting telecine content in an NTSC image signal. The conventional telecine mode detecting

- 2 scheme calculates sums of absolute difference (SAD) for pairs of neighboring fields

and analyses sequences of 5 SAD values.

Referring to Figure 1, the conventional telecine mode detecting apparatus includes a s field buffer 10, a difference calculator 18, an absolute value calculator 20, a field

adder 30, a limiter 40, a band-pass filter 50, a power calculator 60 and a mode detector 70.

The field buffer 10 stores fields of incoming image signals. The field buffer 10

10 includes a first field buffer 12, a second field buffer 14 and a third field buffer 16.

Accordingly, the fields of the incoming image signals are sequentially stored in and

output from the first, the second and the third buffers 12, 14,16.

The difference calculator 18, the absolute value calculator 20 and the field adder 30

Is calculate the SAD of the image signal. The difference calculator 18 calculates the difference between pixels in the satne positions in the different fields that are stored

in the first and the third buffers 12, 16. The absolute value calculator 20 calculates the ab solute values of the pixel differences.

20 The field adder 30 accumulates he absolute pixel difference values in units of one

field. Accordingly, SADs for respective fields of the incoming image signal are

calculated. The limiter 40 limits the amplitude of the SAD, which can be large when a scene 25 changes and is a main cause of defective detection of the telecine mode, to a predetermined threshold.

The band-pass filter 50 filters the limited SADs from the limiter 40, thereby extracting signals having 5-field periods with respect to a frequency axis. The 5

30 field signals, which are output by the band-pass filter 50, are sinusoidal waves.

The power calculator 60 calculates the power of the sinusoidal waves output from the band-pass filter 50. Accordingly, the calculated powers are used to check how much of the SADs of the respective fields have a period of 5 fields.

s The mode detector 70 compares the predetermined threshold and the power calculated by the pourer calculator 60, thereby determining the whether the incoming signal is in telecine mode. That is, the conventional mode detector 70 determines that the incoming image signals are in telecine mode when the power calculated by the power calculator 60 is greater than the predetermined threshold.

10 The conventional mode detector 70 determines that the incoming image signals are in non-telecine mode when the power calculated by the power calculator 60 is less than the predetermined threshold. Also, in accordance to the comparison result between he predetermined threshold and the power calculator 60, the conventional mode detector 70 outputs '1' for the telecine mode and '0' for the non-telecine 15 mode together with the incoming image signals to an IPC unit that performs the IPC process, or to a storage unit that stores the incoming image signals.

Figure 2 is a graph showing the SADs calculated with respect to fields that are

output from the field adder 30 of Figure 1. It is assumed that no noise has occurred

20 during transmission of the 3:2 pulldown concerted image signals (streams).

Referring to Figure 2, a scene change occurs at field no. 9, which prevents finding a

field periodicitv. The limiter 40 limits the amplitude of the SAD at field no. 9 to

the predetermined threshold, thereby eliminating the effect of a scene change. As 25 the band-pass filter 50 filters the limited SAD with a centre frequency at = 2'r /5 and a DC gain at '0', the output SAD is a sinusoidal wave having a period of 1/5 of the field period. As the SAD component having 1/5 field period

increases, a relatively large amplitude sinusoidal signal is obtained. In order to calculate the power with respect to the amplitude of the sinusoidal signal, the power 30 calculator 60 calculates the sum of the squares of the amplitude. Accordingly, after comparing the SOLD with the predetermined threshold, the mode detector 70

- 4 determines that the incoming image signals are in telecine mode when the SAD exceeds the predetermined threshold, and then outputs a determination result.

Usually, the SADs of the two fields of a 3:2 pull-down converted stream (incoming

5 image signal) have a period of the fields. However, this periodicity of the SADs

can be lost or masked as a result of noise is added to the SAI:)s.

Another problem is that an incorrect periodicity of the incoming image signals may be output. That is, when the limiter 40 limits the peak value of the SAD to 10 eliminate the cause of the scene change, the limiter 40 removes a value of the SAD by the predetermined value depending on the 3:2 full-down converted stream even when the value of the SAD is small compared to the predetermined value.

Furthermore, the mode detector 70 has the predetermined threshold to identify Is telecine mode incoming image signals based on the comparison of the SADs. Since incoming streams can have different powers, using a fixed threshold for all the incoming streams can cause unreliable telecine mode detection of the image signals.

In order to overcome the above problem, many candidates for the thresholds have 20 been used to obtain appropriate thresholds. However, with a lot of noise in the incoming stream and great SAD changes between the neighbouring fields, the

telecine mode detection can be quite inaccurate.

According to the present invention, there is provided a method of identifying a 25 telecine signal, the method comprising: receiving a video signal; determining the degree of motion between fields of adjacent frames for a

sequence of frames; and comparing the pattern of inter-held motion determined for said sequence 30 with a reference pattern and identifying the received video signal as telecine if the patterns match.

- 5 According to the present invention, there is also provided an apparatus for identifying a telecine signal, the apparatus comprising: means for receipting a video signal; means for determining the degree of monon between fields of adjacent

s frames for a sequence of frames; and means for comparing the pattern of inter-field motion determined for said

sequence with a reference pattern and identifying the received video signal as telecine if the patterns match.

lo Preferably, the pattern of inter-field motion for said sequence is obtained by

performing integer division on the determined degrees of motion using the same divisor. More preferably, said division is repeated using increasing divisors.

Preferably, the means for determining the degree of motion between fields of

15 adjacent frames for a sequence of frames comprises first, second and third field

buffers configured to store first, second and third sequential fields of a received

video signal and motion determination means for comparing said first and third fields.

20 An embodiment of the present invention will now be described, by way of example, with reference to Figures 3 to 12 of the accompanying drawings, in which: Figure 1 is a block diagram showing a conventional apparatus for detecting a telecine mode in National Television System Committee (NTSC) image signals; Figure 2 is a graph showing SADs calculated with respect to fields output from a

25 field adder of the apparatus shown Figure 1;

Figure 3 is a block diagram showing an apparatus for detecting telecine mode for an image signal according to the present invention; Figure 4 is a graph showing the number of motion blocks of respective fields output

from a motion information buffer of the apparatus shown in Figure 3; 30 Figure 5 is a graph showing the number of motion blocks of respective buffers output from the motion information buffer of the apparatus shown in Figure 3;

- G Figure 6 is a View showing a process of 3:2 pulldown conversion at a transmitting terminal; Figure 7 is a view showing a process of storing motion information for the fields in

the motion information buffer according to calculation of the motion information s of the respective fields of the motion information calculator of the apparatus shown

in Figure 3; Figutc 8 is a view explaining a process of matching a pattern performed by the pattern matching unit of the apparatus shown in Figure 3; Figures 9A, 9B and 9C are tables showing telecine mode detection using gradual 10 quantization with respect to the motion information of the pattern matching unit of the apparatus shown in Figure 3; Figures 10A and 10B are tables showing variations in the pattern addresses for the conlpatison between image signals with lots of noise and the results of gradual quantization with respect to the motion information of the pattern matching unit of 15 the apparatus shown in Figure 3; Figures 11A, 11B and 11C are tables showing the variations in the pattern addresses for the comparison between the image signals with little noise and the results of gradual quantization with respect to the motion information of the pattern matching unit of the apparatus shown in Figure 3; and 20 Figure 12 is a flowchart illustrating a method of detecting telecine mode in image signals using the telecine mode detecting apparatus shown in Figure 3.

Referring to Figure 3, a telecine mode detecting apparatus includes a field buffer

100, a motion information calculator 200, a motion information buffer 300 and a 2s pattern matching unit 400.

The field buffer 100 stores incoming image signals in units of one field and outputs

the stored image signals. In the present example, the incoming image signals are NTSC signals. The held buffer 100 includes a first field buffer 120, a second field

30 buffer 140 and a third field buffer 160. The incoming image signals are sequentially

stored in the first, the second and the third field buffers 12(), 140, 160 and output.

The motion information calculator 200 compares the fields stored in the first and

the third field buffers 120, 160 to obtain motion information in accordance with

motion in the compared fields.

The motion information buffer 300 stores the motion information for pairs of herds, calculated by the motion information calculator 200, and outputs the stored motion information. In this example, the motion information is stored in units of 10 fields.

lo The pattern matching unit 400 compares the motion information stored in the motion information buffer 300 with a field pattern having a regular periodicity

characteristic of 3:2 pulldown conversion, thereby determining that the image signals are in the telecine mode when the motion information matches the field

pattern characteristic to the 3:2 pulldown conversion.

The motion information calculator 200 calculates the motion information for pairs of fields from the respective fields stored in the first and the third field buffers 120,

160 using motion vector calculation, SAD calculation or motion block coefficient (number) calculation methods.

In the motion vector calculation method, the motion information is obtained by estimating the motion of pixels in the fields using the motion vectors of the

respective fields, and converting the estimated motions into vectors. The motion

information calculator 200 can output a sum of the vectors of the respective pixels 2s of the fields, in units of one field, to the motion information buffer 300.

In the SAD calculation method, an absolute value of the difference between pairs of fields stored respectively in the first and the third field buffers 120, 160 is

calculated. The motion information calculator 200 can output to the motion 30 information buffer 300 a sum of SAVs of the pixels of the fields in units of one

field.

- 8 - In the motion block number calculation method, the number of motion blocks is calculated by dividing the fields, stored in the first and the third field buffers 120,

160, into a predetermined number of blocks, comparing a SAD or a motion vector of the corresponding blocks with a predetermined value, and counting the number s of the motion blocks in which the comparison result indicates the occurrence of a certain motion.

The motion information, calculated using one of the above methods, is stored in the motion information buffer 300 in units of a predetermined number of fields.

10 Accordingly, the pattern matching unit 400 gradually quantizes the motion information from the motion information buffer 300, which is in units of the predetermined number of fields, thereby decreasing external influences on the

image signals, such as noise, etc. The gradual quantization represents that the motion information in the units of the predetermined number of fields, stored in

15 the motion information buffer 300, is divided by gradually increasing numbers. The pattern matching unit 400 compares the result of the gradual quantization of the motion information with the reference field pattern characteristic of 3:2 pulldown

conversion, thereby determining whether the image signals are in the telecine mode according to the comparison result, i.e. according to whether the compared values 20 match each other. That is, the pattern matching unit 400 determines the image signals to be in the telecine mode in the case that the value obtained from the quantization on the motion information matches the field pattern characteristic of

3:2 pulldown conversion.

25 Since whether the irDage signals are in the telecine mode is determined according to a comparison between the result of the quantization of the motion information and a reference field pattern characteristic of 3:2 pull-down conversion, computational

requirements for detecting the telecine mode in image signals can be reduced.

Furthermore, because whether the image signals are in the telecine mode is 30 determined with performing the gradual quantization with respect to the motion information, by comparing the respective results of the gradual quantization with the reference field pattern characteristic of 3:2 pulldown conversion to see whether

the respective results match the field pattern, the telecine mode of the image signals

can be detected with higher accuracy. As a result, it is possible to perform a more accurate interlace-to-progressive (IPC) conversion process in accordance with the detected mode of the image signals, and the required storage capacity for the image 5 signals in telecine mode can be reduced.

Each field of an incoming image signal includes a number of blocks each being

either a motion block, indicating the existence of motion, or motionless, or static, block. Referring to Figure 4, the fields of the incoming image signal from field no. 1 to

field no. 30 have small motions which indicates that the image signals are from a

non-telecine source. On the other hand, the fields of image signal from field no.

31 have approximately 500 motion blocks per field, indicating much motion that the

15 image signal is therefore from 3:2 pulldown telecine source.

Referring to Figure 5 which illustrates another situation, the fields of the incoming

image signal from held no. 1 to field no. 3G have approximately 40 to 130 motion

blocks per fields, indicating that the image signal is from a 3:2 pulldown telecine

20 source. After field no. 37, the images signals are from a non-telecine source. In

both cases there is relatively little motion between fields.

Referring to Figure 6, converting the film at 24 frames per second into video signals at 60 fields (i.e. 30 frames) per second includes converting a first frame of the film

25 source into 2 fields of the NTSC signal and converting a second frame of the film

source into 3 fields of the NTSC signal.

More specifically, converting the film source into the 2 fields of the NTSC signals

includes extracting top (odd) and bottom (even) fields from the first frame of the

30 film to construct the fields of the NTSC signal. Furthermore, converting the

second film frame into the 3 fields of the NTSC signals includes extracting top and

- 10 bottom fields from the second frame of the film source and then reextracting either

the top or bottom field to construct 3 fields of the NTSC signal.

In Figure 6, Fnrand FnBdenote top and the bottom fields derived from a frame

s IN of the source film and Fn' and Fn+Bdenote tOp and the bottom herds derived from a frame Fn+ of the source film. Furthermore, Fn+21 and Fn+2B denote top and the bottom fields derived from a frame n'2 of the source film and n+3 and

Fn+3B denote top and the bottom fields derived from a frame +3 of the film source.

10 Usually, a picture sequence, which is converted into an NTSC signal with 60 fields

per second,is repealed overlOfields,i.e., FnT, Fit, Fn+r, Fn+B,

Fn+l,Fn+2B,F,,+2t, Fn+38 Fn+31, and Fn+3B.

Figure 7 shows a characteristic of 3:2 pulldown telecined file, i.e. a motionless field

Is even, five fields). In the case of the motionless field belonging to the top field, the

motion information buffer 300 stores the motion information calculated at the motion information calculator 200 from an address 'O' of the motion information.

In the case of the motionless field belonging to the bottom field, the motion

information buffer 300 stores the motion information calculated at the motion 20 information calculator 200 from an address '5' of the motion information.

Referring to Figure 8, the pattern matching unit 400 compares a reference field

pattern, having a motionless field at every fifth field, with the motion information

stored in the motion information buffer 300 for the corresponding incoming fields

2; to determine whether the field pattern matches the motion information, thereby

detecting telecine mode in the image signal. The reference field pattern has a 'O' for

every fifth field, indicating a static field, and a '1' for every other field. Having the

motion in a fields means that there exists more than one motion block in the field.

The pattern matching unit 400 determines the matching of the field pattern having a

fve-feld period over 10 fields. Accordingly, when the comparison between the 10-

feld field pattern and the motion information indicates that the image signals are in

the non-telecine, the pattern matching unit 400 performs the gradual quanozation 5 with respect to the motion information, and compares the motion information with the pattern in every quantization to determine whether the pattern matches the motion information, thereby determining whether the image signal is telecined film.

More specifically, the pattern matching unit 400 divides the motion information by number 'N', performs the gradual quantization, compares the quantized value with 10 the pattern, and then determines whether the image signals are in telecine mode.

The number 'A' is 2n (n=1, 2, 3,..., m). It is possible that 'n' of His n=1, 2, 4, 7.

As shown in the tables of Figures 9A, 9B and 9C, the pattern matching unit 400 performs pattern matching in units of 14 fields.

Referring to Figure 9A, by the gradual quantization of the motion information, the pattern matching unit 400 compares the result of dividing the motion information by 12X with the reference pattern, matching "O"s to "Offs and "1"s to non-zero motion information values, and thus determines whether the result value matches 20 the pattern. As a result, the pattern matching unit 400 determines that the image signal is in the telecine mode, i.e. that the image signals are of cine film images.

Referring to Figure 9B, the pattern matching unit 400 compares the result of dividing the motion information by 2 with the pattern, and thus determines that the 25 resultant value matches the pattern. As a result, the pattern matching unit 400 determines that the image signal is in telecine mode.

Referring to Figure 9C, the pattern matching unit 400 determines that none of the gradual quantization results (i.e. division bit 2 to 128) match the reference pattern.

30 Accordingly, the pattern matching unit 400 determines that the incoming image signal is in non-telecine mode.

- 12 Referring to Figure 1 OA, it is assumed that the number of motion blocks, i.e. the motion information, in the (n-1)th field is 1215.

As shown in Figure 10A, '607', a first result from dividing 1215 by 2, is compared 5 by the pattern matching unit 400 with the pattern at the address of '1' or another pattern, which corresponds to another address or is different from the pattern at the address of '1'. When it is determined that the pattern does not match the first result, '303', a second result from dividing 1215 by 4, is compared by the pattern matching unit 400 with the pattern at the address of '9'. When it is determined that 10 the pattern does not match the second result,'9', another result from dividing 1215 by 128, is compared by the pattern matching unit 400 with the pattern at the address of '3'. If it is still determined that the pattern does not match another resultant value, the pattern matching unit 400 determines the image signal is not in the telecine mode.

Referring to Figure 10B, it is assumed that the number of motion blocks, i.e. the motion information, in the nth field is 1212.

As shown in Figure 10B, '60G', a first result from dividing 1212, for the nth field, by

20 2, is compared by the pattern matching unit 400 with the pattern at the address of 2'. When it is determined that the pattern does not match, the first resultant value 303', a second result from dividing 1212 by 4, is compared by the pattern matching unit 400 with the pattern at the address of 'O'. When it is determined that the pattern does not match, the second result '75', another result from dividing 1212 by 25 16, is compared by the pattern matching unit 400 with the pattern at the address of 4'. When it is still determined that the pattern does not match the result, the pattern matching unit 400 determines the image signal is not in the telecine mode.

Referring to Figure 11A, it is assumed that the number of motion blocks, i.e. the 30 motion information in the (n-2)th field, is 730.

- 13 As shown in Figure 1 IA, '365', the result of dividing 730 by 2, is compared by the pattern matching unit 400 with the pattern at the address of '9'. When it is determined that the pattern matches the first resultant value, the pattern matching unit 400 determines that the image signal is in the telecine mode.

Referring to Figure ID, it is assumed that the number of motion blocks, i. e., the motion information in the (n-l)th field, is 1.

As shown in Figure l IB, 'O', the resultant value of dividing 1 by 2, is compared by 10 the pattern matching unit 400 with the pattern at the address of 'O'. When it is determined that the pattern matches the resultant value, the pattern matching unit 400 determines that the image signal is in the telecine mode.

Referring to Figure 1 IC'it is assumed that the number of the motion blocks, i.e., 75 the motion information in the nth field is 747.

As shown in Figure TIC, '373', a resultant value of dividing the 747 motion information in the nth field by 2, is compared by the pattern matching unit 400 with

the pattern at the address of'1'. When it is determined that the pattern matches the 20 resultant value, the pattern matching unit 400 determines that the image signals are in the telecine mode.

As described above, whether the image signals are in the telecine mode is determined by performing the gradual quantization with respect to the motion 25 information, and comparing the resultant values in every quantization with the field

pattern according to the 3:2 pull-down conversion to determine whether the resultant values match the field pattern. As a result, whether the image signals are

in the telecine mode can be detected with higher accuracy. Accordingly, a more accurate interface-to-progressive conversion (IPC) process can be performed in 30 accordance with the accurately detected mode of the image signals, and the storage capacity required for image signals in telecine mode can be reduced.

- 14 Referring to Figure 12, in the method of detecting whether the image signals are in telecine mode, using the telecine mode detecting apparatus shown in Figure 3, the field buffer 100 first stores the incoming image signals in units of one field, and

outputs the stored image signals, operation S100. The field buffer 100 includes a

j first field buffer 120, a second field buffer 140 and a third field buffer 160.

Accordingly, in operation S100, fields of the incoming image signals are sequentially

stored in and output from the first, the second and the third field buffers 120, 140,

160. 0 The motion information calculator 200 compares the fields in the first and the third

field buffers 120, 160, thereby calculating motion information in accordance with

the presence of motion in the fields, operation S120.

The motion information buffer 300 stores the motion information, calculated by the 15 motion information calculator 200, and outputs the stored motion information, operation S140. In this embodiment, the motion information of the fields is stored

and output in units of 10 fields.

The pattern matching unit 400 compares the motion information stored in the 20 motion information buffer 300 with the field pattern that has a predetermined

period in accordance with the 3:2 pull-down conversion, to determine whether the motion information matches the reference field pattern and, subsequently, to

determine whether the image signals are in telecine mode in operation S160.

z5 The motion information calculator 200 calculates the motion information from the fields stored in the first and the third field buffers 120, 160, using one of motion

vector calculation, SAD calculation and motion block number calculation methods. The motion information calculated at the motion information calculator 200

is 30 stored in the motion information buffer 300 in the units of a predetermined number of fields. Accordingly, in order to reduce the external influences on the image

signals, such as a noise, the pattern matching unit 400 gradually quantizes the

- 1i motion information from the motion information buffer 300. In every quantization step, the pattern matching unit 400 compares the resultant value of the quantization with the field pattern characteristic of 3:2 pulldown telecine and, subsequently

determines whether the image signals are in telecine mode or not according to 5 whether the resultant value of the quantization matches the field pattern or not. In

other words, when the resultant value of the quantization on the motion information matches the reference field pattern, the pattern snatching unit 400

determines that the image signals are in the telecine mode.

10 As described above, the resultant values of the quantization on the motion information and the field pattern in accordance with the 3:2 pulldown conversion

are compared with the field pattern, and whether the image signals are in the

telecine mode is determined according to whether the resultant value of the quantization matches the field pattern. As a result, computational requirements for

Is detecting whether the image signals are in the telecine mode, can be reduced.

Further, with performing the gradual quantization on the motion information, the resultant value of each quantization is compared with the field pattern in accordance

with the 3:2 pull-down conversion. As a result' whether the image signals are in the 20 telecine mode, can be detected with higher accuracy.

Accordingly, the more accurate IPC method is enabled based on the accurately detected mode of the image signals, and the storage capacity required for the image signals in the telecine mode can be reduced.

Claims

- 16 Claims

1. A method of identifying a telecine signal, the method comprising:.

receiving a video signal; 5 determining the degree of motion between fields of adjacent frames for a

sequence of frames; and comparing the pattern of inter-field motion determined for said sequence

with a reference pattern and identifying the received video signal as telecine if the patterns match.

2. A method according to claim 1, wherein the pattern of inter-field motion for

said sequence is obtained by performing integer division on the determined degrees of motion using the same divisor.

5 3. A method according to claim 2, wherein said division is repeated using increasing divisors.

4. An apparatus for identifying a telecine signal, the apparatus comprising: means for receiving a video signal; 20 means for determining the degree of motion between fields of adjacent

frames for a sequence of frames; and means for comparing the pattern of inter-field motion determined for said

sequence with a reference pattern and identifying the received video signal as telecine if the patterns match.

2s 5. An apparatus according to claim 4, including means for obtaining the pattern of inter-field motion for said sequence by performing integer division on the

determined degrees of motion using the same divisor.

30 6. An apparatus according to claim 5, Therein said division is repeated using ... mcreasng dlvlsors.

- 17 7. An apparatus according to claim 4, 5 or 6, wherein the means for determining the degree of motion between fields of adjacent frames for a sequence

of frames comprises first, second and third held buffers configured to store first, second and third sequential fields of a received video signal and motion

5 determination tncans for comparing said first and third fields.

8. An apparatus for detecting whether an unage signal is in a film mode, comprising a first field buffer, a second held buffer and a third field buffer that

sequentially buffer respective fields of the image signal by order of input, using the

lo respective fields stored in the first, the second and the third field buffers, the

apparatus cornptlsmg: a motion information calculator calculating motion information of the respective fields by comparing variations of a motion in the respective fields stored

in the first and the third field buffers;

15 a motion information buffer storing the motion information in unit of a number of the fields; and

a pattern matching unit determining whether the image signal is in the film mode by comparing the motion information of the respective fields stored in the

unit of the number of fields with a field pattern having a periodicity in accordance

20 with a 3:2 pull-down conversion, and by subsequently determining whether the motion information matches the pattern.

9. The apparatus of claim 8, wherein the motion information calculator calculates the motion information, using one of a calculation of a motion vector of 25 the respective fields stored in the first and the third field buffers, a calculation of a

sum of the calculated motion vector, a calculation of a sum of absolute difference (SAD), a calculation of a sum of the calculated SAD, a calculation of a number of motion blocks, and a calculation of a sum of the motion blocks.

30 10. The apparatus of claim 9, wherein the pattern matching unit performs a gradual quantization on the motion information in which the motion information in the unit of the number of fields is divided by one of gradually increasing numbers,

- 18 to reduce an external influence on the image signal, compares a resultant value of each quantization with the field pattern in accordance with the 3:2 pull-down

conversion, and determines whether the image signal is in the film mode by determining from the comparison result whether the resultant value of the s quantization matches the field pattern.

11. The apparatus of claim 10, wherein the gradually increasing numbers used in the gradual quantization are 2n (n= 1, 2, 3,..., m).

70 12. The apparatus of claim 11, wherein the gradually increasing numbers used in the gradual quantization are 2n, with n being 1, 2, 4 and 7 among 1,2, 3,..., m.

13. The apparatus of claim 12, wherein the field pattern in accordance with the

3:2 pull-down conversion set to be used in the pattern matching unit comprises: if a pattern in which a motionless field appears in a period of five fields.

14. A method of detecting whether an image signal is in a film mode, using respective fields stored in a first field buffer, a second field buffer and a third field

buffer that sequentially buffer the respective fields of the image signal by order of

20 input, the method comprises: calculating motion information of the respective fields by comparing

variations of a monon in the respective fields stored in the first and the third field

buffers; storing the motion information in unit of a number of fields; and

25 determining whether the image signal is in the film mode by comparing the motion information of the respective fields stored in the unit of the number of

fields with a field pattern having a periodicity in accordance with a 3:2 pull-down

conversion, and by subsequently determining whether the motion information matches the pattern.

15. The method of claim 14, wherein the calculating of the motion information comprises:

- 19 calculating the motion information, using one of a calculation of a motion vector of the respective fields stored in the first and the third field buffers, a

calculation of a sum of the calculated motion vector, a calculation of a sum of absolute difference (SAD), a calculation of a sum of the calculated SAD, a is calculation of a number of motion blocks, and a calculation of a sum of the motion blocks. 16. The method of claim 15, wherein the determining of the film mode comprises: 10 performing a gradual quantization on the motion information in which the motion information in the unit of the number of fields is divided by one of

gradually increasing numbers, to reduce an external influence on the image signal, compares a resultant value of each quantizanon with the held pattern in accordance with the 3:2 pull-down conversion, and thereby determines whether the image signal 5 is in the film mode by determining from the comparison result whether the resultant value of the quantization matches the field pattern.

17. The method of claim 16, wherein the gradually increasing numbers used in the gradual quantization are 2" (not, 2, 3,..., m).

18. The method of claim 17, wherein the gradually increasing numbers used in the gradual quantization are 2n, with n being 1, 2, 4 and 7 among 1,2, 3,, m.

19. The method of claim 18, wherein the field pattern in accordance with the 3:2

25 pull-down conversion set to be used in the film mode determining step comprises: a pattern in which a motionless field appears in the period of five fields.

20. An apparatus for detecting whether an image signal is in a film mode, the apparatus comprising: 30 a motion information calculator calculating motion information of respective fields by comparing a variation of a motion in the respective fields;

- 20 a motion information buffer storing the motion information in unit of a predeeerrnined number of fields; and

a pattern matching unit determining whether the image signal is in the film mode by comparing the motion information of the respective fields stored in the

5 unit of the predetermined number of fields with a pattern of the field having a

predetermined periodicity in accordance with a 3:2 pull-down conversion, and by subsequently determining whether the motion information matches the pattern.

21. The apparatus of claim 20, wherein the motion information calculator 10 calculates the motion information, using one of a calculation of a motion vector of the respective fields stored in the first and the third field buffers, a calculation of a

sum of the calculated motion vector, a calculation of a sum Of absolute difference (SAD), a calculation of a sum of the calculated SAD, a calculation of a number of motion blocks, and a calculation of a sum of the motion blocks.

22. An apparatus for detecting whether an image signal having a plurality of fields is in a film mode, the apparatus comprising:

a motion information calculator calculating motion information corresponding to respective ones of the fields; and

20 a pattern matching unit comparing the motion information in unit of a number of the fields, and comparing the motion information with a reference

pattern to determine whether the image signal is in the film mode.

23. The apparatus of claim 22, wherein the reference pattern comprises; 25 patterns formed in the same number as the fields to correspond to the respective

motion information.

24. The apparatus of claim 22, wherein the motion information represents that one of the fields is a motionless field, and the pattern matching unit determines that

30 the image signal is not in the film mode, when the motion information matches the reference pattern.

- 21 25. The apparatus of claim 22, wherein the motion information represents that one of moving information corresponding to the respective fields repeats in every N

fields where N is a positive integer, and the pattern matching unit determines that

the image signal is not in the film mode, when the motion information matches the 5 reference pattern.

26. The apparatus of claim 25, wherein the one of the motion information represents a motionless field.

lo 27. The apparatus of claim 25, wherein the N is S. the one of the motion information represents a motionless field, and the other four of the motion

information represent motion fields.

28. The apparatus of claim 25, wherein the pattern matching unit determines 15 that the image signal is in the film mode, when the motion information does not match the reference pattern.

29. The apparatus of claim 25, wherein the reference pattern comprises a pattern indicating a motionless field and a plurality of motion fields, and the pattern

20 matching unit determines that the image signal is in the film mode, when the motion information does not match the reference pattern.

30. The apparatus of claim 29, wherein the pattern matching unit determines that the image signal is not in the film mode, when the motion information matches 2s the reference pattern.

31. The apparatus of claim 22, wherein the motion information calculator compares variations between motions of the fields to calculate the motion

information of the fields.

32. The apparatus of claim 22, wherein the reference pattern comprises a periodicit--' and the pattern matching unit determines that the image signal is not in

- 22 the film mode, v-hen the motion information includes the same periodicity as the reference pattern.

33. The apparatus of claim 32, wherein the periodicity represents that one of the s motion information is the same as an other one of the motion information.

34. The apparatus of claim 33, wherein the periodicity is generated when the image signal, which is not in film mode, is formed using a 3:2 pull down conversion of a film source image signal of the film mode.

35. The apparatus of claim 33, wherein the one of the fields and the other one of

the fields are generated using a 3:2 pull down conversion of a fun source image

signal in the film mode.

15 36. The apparatus of claim 22, wherein the pattern matching unit divides the motion information by a positive integer to generate second motion information when the motion information does not match the reference pattern.

37. The apparatus of claim 36, wherein the pattern matching unit compares the 20 second motion information with another reference pattern to determine whether the image signal is in the film mode.

38. The apparatus of claim 36, wherein the positive integer is one of 2, 4, 16, and 128. 39. The apparatus of claim 36, wherein the positive integer is a first integer and a second integer, and the pattern matching unit divides the motion information by the first integer to generate the third information when the second motion information does not match the reference pattern, and compares the third information with 30 another reference pattern to determine whether the image signal is in the film mode.

- 23 40. The apparatus o f claim 39, wherein the pattern matching unit divides the motion information by the second integer to generate fourth information when the third motion information does not match the reference pattern, and compares the fourth information with another reference pattern to determine whether the image s signal is in the film mode.

41. The apparatus clef claim 22, wherein the motion information comprises: the number of motion blocks of the respective field.

10 42. The apparatus of claim 41, wherein the pattern matching unit divides the number of the motion blocks by a positive integer to generate the second motion information and compare the second motion information with the reference pattern.

43. The apparatus of claim 22, wherein the reference pattern comprises a 5 plurality of addresses each having respective patterns, and the pattern matching unit compares the motion information with one of the respective patterns corresponding to one of the addresses to determine whether the image signal is in the film mode.

44. The apparatus of claim 22, further comprising: 20 a motion information memory storing the motion information in unit of a number of fields.

45. An apparatus for detecting whether an image signal having a plurality of fields is in a film mode, the apparatus comprising:

25 a motion information calculator calculating motion information of the respective fields; and

a pattern matching unit comparing the motion information corresponding to a group of the fields with a reference pattern to determine whether the image signal

is in the film mode.

46. An apparatus for detecting whether an itnage signal having a plurality of fields is in a film mode, the apparatus comprising:

- 24 a motion information calculator calculating first motion information of respective ones of the fields; and

a pattern matching unit dividing the first motion information of the respective fields by a positive integer to generate second monon information, and

5 comparing the second information with a reference pattern to determine whether the image signal is in the film mode.

47. An apparatus for detecting whether an image signal having a plurality of fields is in a film mode, the apparatus comprising:

70 a motion information calculator calculating the number of motion blocks of respective ones of the fields; and

a pattern matching unit comparing the number of motion blocks of the herds with a reference pattern to determine whether the image signal is in the film mode.

15 48. A method of detecting whether an image signal having a plurality of fields is

in a film mode, the method comprising: calculating motion information of respective ones of the fields;

generating the motion information in unit of a number of the fields; and

comparing the motion information in unit of a number of the fields with a

20 reference pattern to determine whether the image signal is in the film mode.

49. The method of claim 47, wherein the calculating of the first information comprises: calculating the number of motion blocks.

50. The method of claim 47, wherein the generating of the motion information in unit of the number of the fields and the comparing of the motion information

with the reference pattern comprise: dividing the motion information by a positive integer to generate second 30 motion information; and comparing the second information with the reference pattern to determine whether the image signal is in the film mode.

- 25 51. A method of identifying a telecine signal substantially as hereinbefore de scribed.

s 52. An apparatus for identifying a telecine signal substantially as hereinbefore described with reference to Figures 3 to 12 of the accompanying drawings.